Project description:Background and Aims: The impact of cigarette smoke on inflammatory bowel disease has been established by a large number of epidemiological, clinical, and preclinical studies. Exposure to cigarette smoke is associated with a higher risk of developing Crohn’s disease but is inversely correlated with the development, disease risks, progression, and relapse rate of ulcerative colitis. Few mechanistic studies have investigated the effect of cigarette smoke on intestinal inflammation and microbial composition. Methods: Three groups of mice were exposed to three different concentrations of cigarette smoke for a total of 4 weeks, including 5 days of dextran sulfate sodium treatment to induce colitis and a 7-day recovery period. A comprehensive and integrated comparative analysis of the global colon transcriptome and microbiome, as well as classical endpoints, was performed. Results: Cigarette smoke exposure significantly decreased the severity induced colitis. Colon transcriptome analysis revealed that cigarette smoke downregulated specific pathways in a concentration-dependent manner, affecting both the inflammatory state and composition of the gut microbiome. Metagenomics analysis demonstrated that cigarette smoke can modulate dextran sulfate sodium-induced dysbiosis of specific bacterial genera, contributing to resolve the inflammation or accelerate recovery. Conclusions: Cigarette smoke alters gut microbial composition and reduces inflammatory responses in a concentration-dependent manner. The present study lays the foundation for investigating potential molecular mechanisms responsible for the attenuation of colitis by cigarette smoke.
Project description:Gut dysbiosis and host genetics are implicated as causative factors in inflammatory bowel disease, yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically-created blind self-filling (SFL) and self-emptying (SEL) ileal loops. SFL exhibit fecal stasis due to directional peristalsis motility oriented towards away from the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. Germ-free IL10-/- mice conventionalized with wild type SFL, but not SEL, microbiota, develop severe colitis. These data demonstrate an essential role for fecal stasis, gut dysbiosis, and genetic susceptibility and offer insights into human pouchitis and ulcerative colitis.
Project description:The etiology of the inflammatory bowel diseases, including ulcerative colitis, remains incomplete, but recent findings points to the involvement of complex host-microbial interactions. We hypothesized that an analysis of the proteins on the host-microbial interacting surface, the intestinal mucosa, could reveal novel insights into the diseases. Mucosal colonic biopsies were extracted by standard colonscopy from sigmoideum from 10 ulcerative colitis patients from non-inflammed tissue and 10 controls. The biopsies were immediately following extraction snap-frozen for protein analysis and the protein content of the biopsies was characterized by high-throughput quantative gel-free proteomics.
Project description:Morphine causes microbial dysbiosis. In this study we focused on restoration of native microbiota in morphine treated mice and looked at the extent of restoration and immunological consequences of this restoration. Fecal transplant has been successfully used clinically, especially for treating C. difficile infection2528. With our expanding knowledge of the central role of microbiome in maintenance of host immune homeostasis17, fecal transplant is gaining importance as a therapy for indications resulting from microbial dysbiosis. There is a major difference between fecal transplant being used for the treatment of C. difficile infection and the conditions described in our studies. The former strategy is based on the argument that microbial dysbiosis caused by disproportionate overgrowth of a pathobiont can be out-competed by re-introducing the missing flora by way of a normal microbiome transplant. This strategy is independent of host factors and systemic effects on the microbial composition. Here, we show that microbial dysbiosis caused due to morphine can be reversed by transplantation of microbiota from the placebo-treated animals.
Project description:Host-microbiome communication is frequently perturbed in gut pathologies due to microbiome dysbiosis, leading to altered production of bacterial metabolites. Among these, 7a-dehydroxylated bile acids are notably diminished in inflammatory bowel disease patients. Herein, we investigated whether restoration of 7a-dehydroxylated bile acids levels by Clostridium scindens, a human-derived 7a-dehydroxylating bacterium, can reestablish intestinal epithelium homeostasis following colon injury. Gnotobiotic and conventional mice were subjected to chemically-induced experimental colitis following administration of Clostridium scindens. Colonization enhanced the production of 7a-dehydroxylated bile acids and conferred prophylactic and therapeutic protection against colon injury through epithelial regeneration and specification. Computational analysis of human datasets confirmed defects in intestinal cell renewal and differentiation in ulcerative colitis patients while expression of genes involved in those pathways showed a robust positive correlation with 7a-dehydroxylated bile acid levels. Clostridium scindens administration could therefore be a promising biotherapeutic strategy to foster mucosal healing following colon injury by restoring bile acid homeostasis.
Project description:Gut dysbiosis is closely involved in the pathogenesis of inflammatory bowel disease (IBD). However, it remains unclear whether IBD-associated gut dysbiosis plays a primary role in disease manifestation or is merely secondary to intestinal inflammation. Here, we established a humanized gnotobiotic (hGB) mouse system to assess the functional role of gut dysbiosis associated with two types of IBD - Crohn's disease (CD) and ulcerative colitis (UC). In order to explore the functional impact of dysbiotic microbiota in IBD patients on host immune responses, we analyzed gene expression profiles in colonic mucosa of hGB mice colonized with healty (HC), CD, and UC microbiota.
Project description:The etiology of the inflammatory bowel diseases, including ulcerative colitis, remains incomplete, but recent findings points to the involvement of complex host-microbial interactions. We hypothesized that an analysis of the proteins on the host-microbial interacting surface, the intestinal mucosa, could reveal novel insights into the diseases. Mucosal colonic biopsies were extracted by standard colonscopy from sigmoideum from 10 ulcerative colitis patients from non-inflammed tissue and 10 controls. The biopsies were immediately following extraction snap-frozen for protein analysis and the protein content of the biopsies was characterized by high-throughput quantative gel-free proteomics.
Project description:Ulcerative Colitis is an autoimmune inflammatory bowel disease that causes chronic inflammation in the colon and the rectum. Althoung extensively researched, the underlying molecular mechanisms of Ulcerative Colitis remain elusive. Especially, there is a lack of understanding about regulatory non-coding miRNA expression during Ulcerative Colitis. Therefore, we performed high-throughput miRNA profiling of colon tissue biopsies from XX patients with active Ulcerative Colitis, XX patients with quiescent Ulcerative Colitis and XX Symptomatic Control individuals.
Project description:Inflammatory bowel disease (IBD) is characterized by dysbiosis of the gut microbiota and dysfunction of in testinal stem cells (ISCs). However, the direct interactions between IBD microbial factors and ISCs are unde scribed. Here, we identify α2A-adrenergic receptor (ADRA2A) as a highly expressed GPCR in ISCs. Through PRESTO-Tango screening, we demonstrate that tyramine, primarily produced by Enterococcus via tyrosine decarboxylase (tyrDC), serves as a microbial ligand for ADRA2A. Using an engineered tyrDC deficient Enterococcus faecalis strain and intestinal epithelial cell-specific Adra2a knockout mice, we show that Enterococcus-derived tyramine suppresses ISC proliferation, thereby impairing epithelial regeneration and exacerbating DSS-induced colitis through ADRA2A. Importantly, blocking the axis with an ADRA2A antagonist, yohimbine, disrupts tyramine-mediated suppression on ISCs and alleviates colitis.Our findings highlight a microbial ligand-GPCR pair in ISCs, revealing a causal link between microbial regulation of ISCs and colitis exacerbation and yielding a targeted therapeutic approach to restore ISC function in colitis.